Field of the Invention
The invention relates in general to an image processing technology, and more particularly to a method and device for image zoom out processing.
Description of the Related Art
Current methods for image zoom out processing generally directly zoom out an original image to a target image according to a zoom out ratio by a bilinear interpolation algorithm. When the above approach is adopted for an image that needs to be greatly zoomed out, many pixels in the original image are directly omitted. As such, aliases may appear at edges of the zoomed out image, leading to significant degradation in the display accuracy of the image.
For example, assume that the resolution of an original image is 480*640, and the resolution of a target image after a zoom out process is 96*128. In the zoom out process, the value of a pixel in the target image calculated by the bilinear interpolation algorithm is obtained through calculating values of four pixels adjacent to the pixel in the original image. When 480 pixels in an original row are reduced to 96 pixels in a zoomed out row, the 96 pixels of the zoomed out row only involve a maximum of 192 pixels of the original row, while the remaining 288 pixels are omitted. Thus, aliases may appear at edges of the zoomed out image, leading to significant degradation in the display accuracy of the image.